[GAP Forum] Attributes Problem
Michael Hartley
Michael.Hartley at nottingham.edu.my
Tue Jul 25 09:07:37 BST 2006
Attributes, once set, can't be unset. This is wonderful if you plan to
save processor time. The problem I am facing now is that I am running
out of memory.
I have plenty of processing time to throw at this problem, because my
alternative method of solving it
* took a month for this 'test' case
* is taking 2 years for the 'real' case
I have a large pc group (order 2^26), and I want to trace through its
maximal subgroup structure to find certain 'low' index subgroups. Doing
this in a breadth-first manner quickly runs out of memory, since the
number of subgroups rises exponentially with the index. I have a feeling
the -o option won't help me here.
I reprogrammed everything to do a depth-first search - however, since
the computed MaximalSubgroups are stored as an Attribute, I run out of
memory anyway!
I only need each set of MaximalSubgroups once. If GAP can't 'forget' the
MaximalSubgroups of a PC group,
can I instruct it not to 'remember' them in the first place??
Yours, Mike H,..
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